The opening ceremony of the Beijing Olympics [8 August 2008] will inevitably be an occasion for admiring comment about the immense achievements – architectural, organisational and presentational – of the host nation. This, of course, is precisely what the Chinese authorities hoped for when they secured their Olympic bid seven years ago. It was intended as a statement of China's modernity, its economic prowess and its rise to the top table of world power. Judging from the coverage so far, there are plenty of people willing to accept this image at face value. Yes, human rights groups have raised some awkward questions, but why should that spoil the party when so many world leaders will be on hand to give their blessing to the proceedings?

Despite the fact that I campaigned hard for a political boycott of the Beijing Olympics, I wish the athletes well and hope the competition passes without a repeat of the terrorist attack [bomb blasts] that happened earlier this week in Xinjiang province. What I don't want is for those watching to be in any doubt about the nature of the regime these games have been designed to benefit. Beyond the mesmerising Bird's Nest stadium is a country presided over by a terror state responsible for some truly appalling crimes against humanity. Even the stadium's designer, Ai Weiwei, was moved to disown the games describing the human rights situation as "appalling". The countless victims imprisoned, tortured and murdered by the Chinese state also deserve to be part of this Olympic story. They should not be too far from our thoughts as the gold medals are being handed out.

Both Amnesty International and Human Rights Watchare in agreement that far from honouring their pledge to improve human rights as a result of hosting the Olympics, the Chinese authorities have used the games as an excuse to intensify domestic repression. Much of this abysmal record is widely known about. There is no freedom of expression and the authorities go to extraordinary lengths to control information and restrict access to the internet. Dissent is punished severely, with those considered a threat imprisoned without trial and often without any information about their location or condition. The death penalty is applied extensively and for relatively minor non-violent crimes like tax fraud. The use of torture is frequent according to Manfred Nowak, the UN's special rapporteur on torture, including beatings, electrocution and the removal of fingernails. The violent suppression of Tibetan rights and cultural identity is well documented. Moreover, some of these methods appear to be for export. BBC Panorama recently exposed China's role in arming the Sudanese government in its genocidal campaign in Darfur.

The victims of Chinese state terror are numerous and include human rights defenders, lawyers, trade unionists, environmentalists, campaigners for regional autonomy and anyone who seeks to challenge state policy. One person I am particularly concerned about is Gao Zhisheng, a Nobel prize nominee sometimes referred to as "China's conscience". As one of his country's top lawyers, he was targeted by the regime for speaking out about human rights abuses and has been in detention and subjected to torture since he wrote a critical open letter about the Olympics last year [2007]. It is essential that the UK and other countries across the world raise his case with the Chinese authorities as a matter of urgency.

One of the groups that Gao has been most prominent in defending has been the religious movement, Falun Gong. Members of this group have been on the receiving end of some of the most brutal abuse imaginable. Many foreign observers are easily frightened off by the Chinese government's designation of it as an "evil cult", but Falun Gong is a harmless Buddha-school set of spiritual exercises that is persecuted mainly because its popularity is deemed to pose a threat to the "guiding role" of the Chinese Communist party. A decade ago it had up to 100 million adherents.

Falun Gong supporters are routinely imprisoned for their beliefs and are believed by Manfred Nowak to make up the majority of prisoners subjected to torture. But they are also the principal victims of China's most horrific crime against humanity – the harvesting of human organs from prisoners to supply the country's burgeoning transplant business. With transplants running at more than 10,000 a year, and with a harvested heart fetching up to $160,000, this is a profitable enterprise for the People's Liberation Army which organises it and pockets the proceeds.

Unfortunately the organs used are far from surplus to requirements. A report written last year [2007] by the former Canadian secretary of state, David Kilgour, and the human rights lawyer, David Matas, concluded: "there has been and continues today to be large scale organ seizures from unwilling Falun Gong practitioners." Falun Gong prisoners are the only ones routinely subjected to urine and blood tests, with strong reason to believe that significant numbers of them are subsequently killed to order.

There is no sign that this appalling practice is about to stop, either. Earlier this year, the Chinese authorities announced that they were adopting a lethal injection as the means of capital punishment instead of a bullet through the head – the mouth was propped open to minimise damage, but it is still a messy way to kill. It is not hard to understand this change. In one province alone, 16 buses have been specially adapted to perform on-the-spot eviscerations.

This is the reality behind the facade of modernity presented by the Beijing Olympics. Although the political boycott of the opening ceremony will be nothing like as widespread as the seriousness of the human rights situation in China demands, it is not too late to register a protest against the terror state behind these games. I hope that Gordon Brown will reconsider his decision to attend the closing ceremony later this month [August 2008]. I also hope that those watching at home will take some time out from enjoying the sport to consider the enormous human suffering that is the reality of daily life for many Chinese people.